Toll-IL-1-receptor-containing adaptor molecule-1: a signaling adaptor linking innate immunity to adaptive immunity

Alterations of receptors and insulin-like growth factor binding proteins in senescent cells

The knowledge about cellular senescence expands dynamically, providing more and more conclusive evidence of its triggers, mechanisms, and consequences. Senescence-associated secretory phenotype (SASP), one of the most important functional traits of senescent cells, is responsible for a large extent of their context-dependent activity. Both SASP's components and signaling pathways are well-defined. A literature review shows, however, that a relatively underinvestigated aspect of senescent cell autocrine and paracrine activity is the change in the production of proteins responsible for the reception and transmission of SASP signals, i.e., receptors and binding proteins. For this reason, we present in this article the current state of knowledge regarding senescence-associated changes in cellular receptors and insulin-like growth factor binding proteins. We also discuss the role of these alterations in senescence induction and maintenance, pro-cancerogenic effects of senescent cells, and aging-related structural and functional malfunctions.

Amphiphilic Block Copolymer Nanostructures as a Tunable Delivery Platform: Perspective and Framework for the Future Drug Product Development

Nanoformulation of active payloads or pharmaceutical ingredients (APIs) has always been an area of interest to achieve targeted, sustained, and efficacious delivery. Various delivery platforms have been explored, but loading and delivery of APIs have been challenging because of the chemical and structural properties of these molecules. Polymersomes made from amphiphilic block copolymers (ABCPs) have shown enormous promise as a tunable API delivery platform and confer multifold advantages over lipid-based systems. For example, a COVID booster vaccine comprising polymersomes encapsulating spike protein (ACM-001) has recently completed a Phase I clinical trial and provides a case for developing safe drug products based on ABCP delivery platforms. However, several limitations need to be resolved before they can reach their full potential. In this Perspective, we would like to highlight such aspects requiring further development for translating an ABCP-based delivery platform from a proof of concept to a viable commercial product.

Downregulated TICAM1 is a prognostic biomarker and associated with immune tolerance of Wilms tumor patients

Background

TIR domain containing adaptor molecule 1 (TICAM1) is a coding gene participating in immune and inflammation responses to malignant cells. However, the role of TICAM1 in Wilms tumor (WT) is rarely known.

Materials and methods

The expression level of TICAM1 was calculated in the WT TARGET cohort and validated using the GSE66405 cohort. The Kaplan–Meier method was employed to investigate the potential clinical value of TICAM1 and the association between its expression level and clinical features. The influence of TICAM1 on immune infiltration was examined by ESTIMATE, CIBERSORT and MCPcounter algorithms. IC50 of chemotherapeutic drugs was calculated by “pRRophetic” R package.

Results

TICAM1 was downregulated in WT patients with worse prognosis and a more advanced clinical stage. Moreover, a low expression level of TICAM1 contributed to less immune cell infiltration, few protective immune cells and more antitumor immune cells.

Conclusions

TICAM1 exerts a significant impact on the prognosis, progression and immune infiltration condition of WT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01326-5.

Activation of Innate Immunity by Therapeutic Nucleic Acids

Nucleic acid-based therapeutics have gained increased attention during recent decades because of their wide range of application prospects. Immunostimulatory nucleic acids represent a promising class of potential drugs for the treatment of tumoral and viral diseases due to their low toxicity and stimulation of the body’s own innate immunity by acting on the natural mechanisms of its activation. The repertoire of nucleic acids that directly interact with the components of the immune system is expanding with the improvement of both analytical methods and methods for the synthesis of nucleic acids and their derivatives. Despite the obvious progress in this area, the problem of delivering therapeutic acids to target cells as well as the unresolved issue of achieving a specific therapeutic effect based on activating the mechanism of interferon and anti-inflammatory cytokine synthesis. Minimizing the undesirable effects of excessive secretion of inflammatory cytokines remains an unsolved task. This review examines recent data on the types of immunostimulatory nucleic acids, the receptors interacting with them, and the mechanisms of immunity activation under the action of these molecules. Finally, data on immunostimulatory nucleic acids in ongoing and completed clinical trials will be summarized.

The Immunopathobiology of SARS-CoV-2 Infection

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to coronavirus disease 2019 (COVID-19). Virus-specific immunity controls infection, transmission and disease severity. With respect to disease severity, a spectrum of clinical outcomes occur associated with age, genetics, comorbidities and immune responses in an infected person. Dysfunctions in innate and adaptive immunity commonly follow viral infection. These are heralded by altered innate mononuclear phagocyte differentiation, activation, intracellular killing and adaptive memory, effector, and regulatory T cell responses. All of such affect viral clearance and the progression of end-organ disease. Failures to produce effective controlled antiviral immunity leads to life-threatening end-organ disease that is typified by the acute respiratory distress syndrome. The most effective means to contain SARS-CoV-2 infection is by vaccination. While an arsenal of immunomodulators were developed for control of viral infection and subsequent COVID-19 disease, further research is required to enable therapeutic implementation.

Heterologous Expression and Assembly of Human TLR Signaling Components in Saccharomyces cerevisiae

Toll-like receptor (TLR) signaling is key to detect pathogens and initiating inflammation. Ligand recognition triggers the assembly of supramolecular organizing centers (SMOCs) consisting of large complexes composed of multiple subunits. Building such signaling hubs relies on Toll Interleukin-1 Receptor (TIR) and Death Domain (DD) protein-protein interaction domains. We have expressed TIR domain-containing components of the human myddosome (TIRAP and MyD88) and triffosome (TRAM and TRIF) SMOCs in Saccharomyces cerevisiae, as a platform for their study. Interactions between the TLR4 TIR domain, TIRAP, and MyD88 were recapitulated in yeast. Human TIRAP decorated the yeast plasma membrane (PM), except for the bud neck, whereas MyD88 was found at cytoplasmic spots, which were consistent with endoplasmic reticulum (ER)-mitochondria junctions, as evidenced by co-localization with Mmm1 and Mdm34, components of the ER and Mitochondria Encounter Structures (ERMES). The formation of MyD88-TIRAP foci at the yeast PM was reinforced by co-expression of a membrane-bound TLR4 TIR domain. Mutations in essential residues of their TIR domains aborted MyD88 recruitment by TIRAP, but their respective subcellular localizations were unaltered. TRAM and TRIF, however, did not co-localize in yeast. TRAM assembled long PM-bound filaments that were disrupted by co-expression of the TLR4 TIR domain. Our results evidence that the yeast model can be exploited to study the interactions and subcellular localization of human SMOC components in vivo.

Host Components That Modulate the Disease Caused by hMPV

Human metapneumovirus (hMPV) is one of the main pathogens responsible for acute respiratory infections in children up to 5 years of age, contributing substantially to health burden. The worldwide economic and social impact of this virus is significant and must be addressed. The structural components of hMPV (either proteins or genetic material) can be detected by several receptors expressed by host cells through the engagement of pattern recognition receptors. The recognition of the structural components of hMPV can promote the signaling of the immune response to clear the infection, leading to the activation of several pathways, such as those related to the interferon response. Even so, several intrinsic factors are capable of modulating the immune response or directly inhibiting the replication of hMPV. This article will discuss the current knowledge regarding the innate and adaptive immune response during hMPV infections. Accordingly, the host intrinsic components capable of modulating the immune response and the elements capable of restricting viral replication during hMPV infections will be examined.

Recent Advances: The Imbalance of Immune Cells and Cytokines in the Pathogenesis of Hepatocellular Carcinoma

Recent advancement in the immunological understanding of genesis of hepatocellular carcinoma (HCC) has implicated a decline in anti-tumour immunity on the background of chronic inflammatory state of liver parenchyma. The development of HCC involves a network of immunological activity in the tumour microenvironment involving continuous interaction between tumour and stromal cells. The reduction in anti-tumour immunity is secondary to changes in various immune cells and cytokines, and the tumour microenvironment plays a critical role in modulating the process of liver fibrosis, hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), tumor invasion and metastasis. Thus, it is considered as one of primary factor behind the despicable tumour behavior and observed poor survival; along with increased risk of recurrence following treatment in HCC. The primary intent of the present review is to facilitate the understanding of the complex network of immunological interactions of various immune cells, cytokines and tumour cells associated with the development and progression of HCC.

Decreased CD4+CD25+CD127dim/- Regulatory T Cells and T Helper 17 Cell Responsiveness to Toll-Like Receptor 2 in Chronic Hepatitis C Patients with Daclatasvir Plus Asunaprevir Therapy

Direct-acting antivirals (DAAs) not only rapidly inhibited hepatitis C virus (HCV) replication but also modulated innate and adaptive immune response in chronic hepatitis C patients. However, the regulatory activity of DAAs to Toll-like receptor 2 (TLR2) stimulation on CD4⁺CD25⁺CD127^dim/- regulatory T cells (Tregs) and T helper (Th) 17 cells was not completely understood. In the present study, a total of 23 patients with chronic HCV genotype 1b infection were enrolled, and blood samples were collected at baseline (treatment naive), end of therapy (EOT), and 12 weeks after EOT (SVR12) with daclatasvir plus asunaprevir therapy. TLR2 expression on Tregs and Th17 cells was measured by flow cytometry. Cellular proliferation, cytokine production, and suppressive activity were also tested in purified CD4⁺CD25⁺CD127^dim/- Tregs in response to the stimulation of Pam3Csk4, an agonist of TLR2. Inhibition of HCV RNA by daclatasvir and asunaprevir did not affect either percentage of Tregs/Th17 cells or TLR2 expression on Tregs/Th17 cells. Pam3Csk4 stimulation also did not influence either cellular proliferation or Tregs/Th17 proportion at each time point. Stimulation with Pam3Csk4 only enhanced the suppressive function and interleukin (IL)-35 production by Tregs purified from baseline, but not those from EOT or SVR12. Similarly, Pam3Csk4 stimulation only elevated Th17 cell frequency of CD4⁺ T cells from baseline, but not those from EOT or SVR12. Moreover, daclatasvir and asunaprevir therapy did not promote TLR2-induced shift of Tregs toward Th17-like phenotype and function. These data suggested that daclatasvir plus asunaprevir therapy resulted in the decreased responsiveness of Tregs/Th17 cells to TLR2 stimulation in chronic hepatitis C patients, which might provide a novel mechanism underlying DAA-induced immunoregulation.

NF-κB and IRF pathways: cross-regulation on target genes promoter level

Background

The NF-κB and IRF transcription factor families are major players in inflammation and antiviral response and act as two major effectors of the innate immune response (IIR). The regulatory mechanisms of activation of these two pathways and their interactions during the IIR are only partially known.

Results

Our in silico findings report that there is cross-regulation between both pathways at the level of gene transcription regulation, mediated by the presence of binding sites for both factors in promoters of genes essential for these pathways. These findings agree with recent experimental data reporting crosstalk between pathways activated by RIG-I and TLR3 receptors in response to pathogens.

Conclusions

We present an extended crosstalk diagram of the IRF - NF-κB pathways. We conclude that members of the NF-κB family may directly impact regulation of IRF family, while IRF members impact regulation of NF-κB family rather indirectly, via other transcription factors such as AP-1 and SP1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1511-7) contains supplementary material, which is available to authorized users.

INAM plays a critical role in IFN-γ production by NK cells interacting with polyinosinic-polycytidylic acid-stimulated accessory cells

Polyinosinic-polycytidylic acid strongly promotes the antitumor activity of NK cells via TLR3/Toll/IL-1R domain-containing adaptor molecule 1 and melanoma differentiation-associated protein-5/mitochondrial antiviral signaling protein pathways. Polyinosinic-polycytidylic acid acts on accessory cells such as dendritic cells (DCs) and macrophages (Mφs) to secondarily activate NK cells. In a previous study in this context, we identified a novel NK-activating molecule, named IFN regulatory factor 3-dependent NK-activating molecule (INAM), a tetraspanin-like membrane glycoprotein (also called Fam26F). In the current study, we generated INAM-deficient mice and investigated the in vivo function of INAM. We found that cytotoxicity against NK cell-sensitive tumor cell lines was barely decreased in Inam(-/-) mice, whereas the number of IFN-γ-producing cells was markedly decreased in the early phase. Notably, deficiency of INAM in NK and accessory cells, such as CD8α(+) conventional DCs and Mφs, led to a robust decrease in IFN-γ production. In conformity with this phenotype, INAM effectively suppressed lung metastasis of B16F10 melanoma cells, which is controlled by NK1.1(+) cells and IFN-γ. These results suggest that INAM plays a critical role in NK-CD8α(+) conventional DC (and Mφ) interaction leading to IFN-γ production from NK cells in vivo. INAM could therefore be a novel target molecule for cancer immunotherapy against IFN-γ-suppressible metastasis.